1. Field of the Invention
The present invention relates to agricultural vehicles, and, more particularly, to straw hoods in agricultural vehicles.
2. Description of the Related Art
An agricultural harvester known as a “combine” is historically termed such because it combines multiple harvesting functions with a single harvesting unit, such as picking, threshing, separating and cleaning. A combine includes a header which removes the crop from a field, and a feeder housing which transports the crop matter into a threshing rotor. The threshing rotor rotates within a perforated housing, which may be in the form of adjustable concaves and performs a threshing operation on the crop to remove the grain. Once the grain is threshed, it falls through perforations in the concaves onto a grain pan. From the grain pan, the grain is cleaned using a cleaning system, and is then transported to a grain tank onboard the combine. A cleaning fan blows air through the sieves to discharge straw, chaff and other debris toward the rear of the combine.
During the process of harvesting, crop material other than grain (MOG) is intended to be expelled from the combine. This material is usually derived from one of two areas, the threshing rotor or the cleaning system. The material expelled from the threshing rotor is generally referred to as straw and the material expelled from the cleaning system is generally referred to as chaff. This crop residue can be dealt with in several ways, generally categorized as spread and windrowed.
Spread refers to using a mechanical device to distribute the straw and/or chaff evenly across the width of the combine header cut width. This spread material is usually chopped to as short a length as possible so that when it is spread it will break down as quickly as possible and not interfere with tillage or seeding operations.
Windrowing refers to the process of dropping straw directly behind the combine in a continuous stream. The purpose of doing this is usually to allow post harvest processing of the straw such as shaping it into bales. In this process, the straw is usually allowed to pass through the combine with as little interference as possible so that it remains as close as possible to its original length and condition.
Combines have been developed that have one spreader system capable of both spreading and windrowing crop material from the combine during operation, without the need to stop and reconfigure the spreader system. Such a combine is taught, for example, by U.S. Patent Application Publication No. 2015/0011275 to Murray et al. The combine taught by Murray et al. is conveniently changeable between a spreading mode and a windrowing mode. However, the rear straw door can create an abrupt blockage of the exit trajectory of the crop material when in the spreading mode. This abrupt change in trajectory can cause uneven feeding to the spreaders and blockages of the rear hood.
What is needed in the art is a harvester that is conveniently changeable between a spreading mode and a windrowing mode and can more evenly feed the spreaders with crop material.